Re: Re: [PATCH v8 09/10] vduse: Introduce VDUSE - vDPA Device in Userspace

[Yongji Xie]

On Wed, Jun 23, 2021 at 11:31 AM Jason Wang <jasowang@xxxxxxxxxx> wrote:
>
>
> 在 2021/6/22 下午4:14, Yongji Xie 写道:
> > On Tue, Jun 22, 2021 at 3:50 PM Jason Wang <jasowang@xxxxxxxxxx> wrote:
> >>
> >> 在 2021/6/22 下午3:22, Yongji Xie 写道:
> >>>> We need fix a way to propagate the error to the userspace.
> >>>>
> >>>> E.g if we want to stop the deivce, we will delay the status reset until
> >>>> we get respose from the userspace?
> >>>>
> >>> I didn't get how to delay the status reset. And should it be a DoS
> >>> that we want to fix if the userspace doesn't give a response forever?
> >>
> >> You're right. So let's make set_status() can fail first, then propagate
> >> its failure via VHOST_VDPA_SET_STATUS.
> >>
> > OK. So we only need to propagate the failure in the vhost-vdpa case, right?
>
>
> I think not, we need to deal with the reset for virtio as well:
>
> E.g in register_virtio_devices(), we have:
>
>          /* We always start by resetting the device, in case a previous
>           * driver messed it up.  This also tests that code path a
> little. */
>        dev->config->reset(dev);
>
> We probably need to make reset can fail and then fail the
> register_virtio_device() as well.
>

OK, looks like virtio_add_status() and virtio_device_ready()[1] should
be also modified if we need to propagate the failure in the
virtio-vdpa case. Or do we only need to care about the reset case?

[1] https://lore.kernel.org/lkml/20210517093428.670-1-xieyongji@xxxxxxxxxxxxx/

Thanks,
Yongji